He attended The Praia Vermelha Military School in Rio de Janeiro and had a legalist position in the many military revolts of the 1920s and early 1930s. During the 1930 Revolution Mascarenhas kept his loyalty to President Washington Luiz and was arrested by the rebels headed by Getúlio Vargas, who became president himself in that same year after ousting Washington Luiz. After release, Mascarenhas continued his career in the army and was put under arrest for a second time in 1932 when he proclaimed his support for a military and civil uprising against Vargas in São Paulo during 1932. Once again, after the defeat of the uprising, Mascarenhas was released and not prosecuted.

In 1935, while serving in the Realengo Military School, Mascarenhas de Morais took part in the fight against a communist uprising in Rio de Janeiro. This time his loyalty was with the constitutional government of Getulio Vargas. In 1937 he became a General and was, in the following years,...Read More